WO2023224322A1 - Électrolyte pour batterie au lithium rechargeable et batterie au lithium rechargeable le comprenant - Google Patents

Électrolyte pour batterie au lithium rechargeable et batterie au lithium rechargeable le comprenant Download PDF

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WO2023224322A1
WO2023224322A1 PCT/KR2023/006459 KR2023006459W WO2023224322A1 WO 2023224322 A1 WO2023224322 A1 WO 2023224322A1 KR 2023006459 W KR2023006459 W KR 2023006459W WO 2023224322 A1 WO2023224322 A1 WO 2023224322A1
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lithium secondary
electrolyte solution
weight
secondary battery
electrolyte
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PCT/KR2023/006459
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English (en)
Korean (ko)
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심유진
심유나
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에스케이이노베이션 주식회사
에스케이온 주식회사
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Publication of WO2023224322A1 publication Critical patent/WO2023224322A1/fr

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0567—Liquid materials characterised by the additives
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0025—Organic electrolyte
    • H01M2300/0028—Organic electrolyte characterised by the solvent
    • H01M2300/0037—Mixture of solvents
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to an electrolyte for lithium secondary batteries and a lithium secondary battery containing the same. More specifically, it relates to an electrolyte solution for a lithium secondary battery containing a solvent and an electrolyte salt, and a lithium secondary battery containing the same.
  • Secondary batteries are batteries that can be repeatedly charged and discharged, and are widely used as a power source for portable electronic devices such as mobile phones and laptop PCs.
  • Lithium secondary batteries are being actively developed and applied because they have high operating voltage and energy density per unit weight, and are advantageous in charging speed and weight reduction.
  • a lithium secondary battery may include an electrode assembly including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, and an electrolyte solution impregnating the electrode assembly.
  • Lithium metal oxide can be used as an active material for the positive electrode of a lithium secondary battery.
  • the lithium metal oxide include nickel-based lithium metal oxide.
  • lithium secondary battery that provides uniform output and capacity even during repeated charging and discharging is desirable.
  • the output and capacity may decrease due to surface damage of the nickel-based lithium metal oxide used as the positive electrode active material, and a side reaction between the nickel-based lithium metal oxide and the electrolyte may occur. It may be possible.
  • lithium secondary batteries are exposed to high temperature environments during repeated charging and discharging and overcharging. In this case, the above-described problems are accelerated, causing battery expansion (generating gas inside the battery, increasing battery thickness), increasing internal resistance of the battery, and deteriorating battery life characteristics.
  • One object of the present invention is to provide an electrolyte solution for lithium secondary batteries that has excellent high-temperature characteristics and other performances (eg, initial resistance, rapid charging performance, room temperature capacity characteristics, etc.).
  • One object of the present invention is to provide a lithium secondary battery with excellent high-temperature characteristics and other performances (eg, initial resistance, rapid charging performance, room temperature capacity characteristics, etc.).
  • Electrolyte solutions for lithium secondary batteries include an additive containing a compound represented by Formula 1; organic solvent; and lithium salts.
  • R 1 and R 2 are each independently a substituted or unsubstituted cyclic ether group of C 2 -C 8
  • L 1 and L 2 are each independently a substituted or unsubstituted C 1 -C 5 It may be an alkylene group.
  • R 1 and R 2 are each independently an unsubstituted cyclic ether group of C 2 -C 5
  • L 1 and L 2 are each independently an unsubstituted C 1 -C 3 cyclic ether group. It may be an alkylene group.
  • R 1 and R 2 may each independently be an unsubstituted C 4 cyclic ether group, and L 1 and L 2 may each independently be an unsubstituted C 1 alkylene group.
  • the additive may be included in an amount of 0.1 to 5% by weight based on the total weight of the electrolyte solution.
  • the additive may be included in an amount of 0.2 to 2% by weight based on the total weight of the electrolyte solution.
  • the organic solvent may include a linear carbonate-based solvent and a cyclic carbonate-based solvent.
  • the electrolyte solution may further include at least one auxiliary additive selected from the group consisting of cyclic carbonate-based compounds, fluorine-substituted carbonate-based compounds, sultone-based compounds, cyclic sulfate-based compounds, and phosphate-based compounds. there is.
  • the auxiliary additive may be included in an amount of 0.05 to 10% by weight based on the total weight of the electrolyte solution.
  • the auxiliary additive may be included in an amount of 0.1 to 5% by weight based on the total weight of the electrolyte solution.
  • the weight ratio of the auxiliary additive to the weight of the additive in the electrolyte solution may be 0.1 to 10.
  • a lithium secondary battery includes an electrode assembly in which a plurality of positive electrodes and a plurality of negative electrodes are repeatedly stacked; a case accommodating the electrode assembly; And it may include an electrolyte solution for a lithium secondary battery accommodated together with the electrode assembly in the case.
  • Electrolyte solutions containing additives for electrolyte solutions for lithium secondary batteries may form a solid solid electrolyte interphase (SEI) on the electrode surface.
  • SEI solid solid electrolyte interphase
  • lithium secondary battery with improved high-temperature storage characteristics (e.g., the effect of preventing battery capacity maintenance, resistance increase, and thickness increase) at high temperatures.
  • the electrolyte for a lithium secondary battery can implement a lithium secondary battery with improved other characteristics (e.g., reduced initial resistance, improved rapid charge life capacity maintenance rate, low temperature capacity, and improved life capacity maintenance rate at 25°C). You can.
  • improved other characteristics e.g., reduced initial resistance, improved rapid charge life capacity maintenance rate, low temperature capacity, and improved life capacity maintenance rate at 25°C. You can.
  • FIG. 1 is a plan view schematically showing a lithium secondary battery according to example embodiments.
  • Figure 2 is a cross-sectional view schematically showing a lithium secondary battery according to example embodiments.
  • Figure 3 shows H-NMR results of the additive represented by Chemical Formula 1-1 according to one example.
  • ⁇ -based compound may mean a compound to which “ ⁇ -based compound” is attached, and a derivative of the compound.
  • C a -C b may mean “the number of carbon (C) atoms from a to b.”
  • Electrolyte solutions for lithium secondary batteries include lithium salt; organic solvent; And it may include an additive containing a compound represented by Formula 1.
  • Electrolytes for lithium secondary batteries can implement lithium secondary batteries with excellent high-temperature characteristics and other characteristics.
  • Electrolyte solutions for lithium secondary batteries may include an additive containing the compound represented by Chemical Formula 1.
  • each R 1 and R 2 are independent and may be the same or different from each other.
  • R 1 may be a substituted or unsubstituted cyclic ether group of C 2 -C 8 .
  • R 1 may be an unsubstituted C 2 -C 5 cyclic ether group, and more preferably an unsubstituted C 4 cyclic ether group.
  • R 2 may be a substituted or unsubstituted cyclic ether group of C 2 -C 8 .
  • R 1 may be an unsubstituted C 2 -C 5 cyclic ether group, and more preferably an unsubstituted C 4 cyclic ether group.
  • R 1 and R 2 are each independent from each other and may be the same or different.
  • L 1 may be a substituted or unsubstituted C 1 -C 5 alkylene group, preferably L 1 may be an unsubstituted C 1 -C 3 alkylene group, and more preferably L 1 may be an unsubstituted C 1 alkylene group.
  • the cyclic ether group may refer to a heterocyclic compound containing an ether bond in a ring made of an alkyl group.
  • the alkyl group may mean a partial structure remaining assuming that one hydrogen atom is removed from an alkane (C n H 2n+2 ).
  • CH 3- CH 2 -CH 2 - may refer to a propyl group.
  • the alkylene group may refer to a form in which one hydrogen atom is removed from each of the carbon atoms at both ends of an alkane (-C n H 2n -).
  • -CH 2 -CH 2 -CH 2 - may mean a propylene group.
  • the ether may refer to a compound in which two carbons are bonded to the same oxygen atom.
  • CH 3 -O-CH 3 may mean dimethyl ether.
  • substituted may mean that the hydrogen atom of the alkylene group is replaced with a substituent, so that a substituent may be further bonded to the carbon atom of the alkylene group.
  • the substituents include halogen, C 1 -C 6 alkyl group, C 2 -C 6 alkenyl group, amino group, C 1 -C 6 alkoxy group, C 3 -C 7 cycloalkyl group, and 5-7 each. It may be at least one of the heterocycloalkyl groups.
  • the substituent may be halogen or a C 1 -C 6 alkyl group.
  • a film with relatively reduced resistance can be formed on the electrode through a decomposition reaction of the cyclic ether group.
  • SEI can be formed on the cathode. Therefore, decomposition of the organic solvent can be effectively prevented, and gas generation and increase in battery thickness can be significantly reduced.
  • a film with relatively reduced resistance can prevent initial resistance from increasing, which can significantly improve fast charging performance by increasing the mobility of lithium ions.
  • room temperature characteristics and initial resistance characteristics as well as high-temperature storage characteristics can be improved.
  • the compound represented by Formula 1 may include Bis((tetrahydrofuran-2-yl)methyl) sulfite.
  • Bis((tetrahydrofuran-2-yl)methyl) sulfite can be represented by Chemical Formula 1-1.
  • a stable SEI film can be formed on the negative electrode by the sulfite group, resulting in a lithium secondary battery with improved high-temperature storage characteristics. It can be implemented.
  • gas generation can be reduced by suppressing decomposition of the electrolyte due to the reaction between the electrolyte and the cathode.
  • the additive content in consideration of sufficient passivation and stable SEI film formation, is 0.1% by weight or more, 0.2% by weight or more, 0.3% by weight or more, 0.4% by weight or more, 0.5% by weight or more, or It can be adjusted to 1% by weight or more.
  • the additive content is 10% by weight or less, 9% by weight or less, 7% by weight or less, 6% by weight or less, 5% by weight or less, 4.5% by weight or less, based on the total weight of the electrolyte. It can be adjusted to less than % by weight, less than 4% by weight, less than 3.5% by weight, less than 3% by weight, or less than 2% by weight.
  • the content of the additive may be 0.1 to 5% by weight, more preferably 0.2 to 2% by weight.
  • the content of the additive may be 0.1 to 5% by weight, more preferably 0.2 to 2% by weight.
  • the electrolyte solution for a lithium secondary battery according to exemplary embodiments may further include an auxiliary additive in addition to the additives described above.
  • the auxiliary additive may include, for example, a cyclic carbonate-based compound, a fluorine-substituted carbonate-based compound, a sultone-based compound, a cyclic sulfate-based compound, and a phosphate-based compound.
  • the content of the auxiliary additive is, for example, 10% by weight or less, 9% by weight or less, 8% by weight or less of the total weight of the non-aqueous electrolyte solution, considering the action with the main additive containing the compound represented by Formula 1. It can be adjusted to % by weight or less, 7% by weight or less, 6% by weight or less, 5% by weight or less, 4% by weight or less, 3% by weight or less, 2% by weight or less, and 1% by weight or less.
  • the content of the auxiliary additive is 0.01% by weight or more, 0.02% by weight or more, 0.03% by weight or more, 0.05% by weight or more, 0.1% by weight or more, 0.2% by weight or more, 0.3% by weight or more, 0.4% by weight or more. It can be adjusted to more than 0.5% by weight or more than 0.5% by weight.
  • the auxiliary additive may be included in an amount of about 0.05 to 10% by weight, more preferably 0.1 to 5% by weight, based on the total weight of the non-aqueous electrolyte solution.
  • the durability of the electrode protection film can be improved without impairing the role of the main additive, and it can help improve high-temperature storage characteristics and other characteristics.
  • the weight ratio of the auxiliary additive to the weight of the additive in the electrolyte solution may be 0.1 to 10, greater than 1 to 10 or less, and 5 to 10 or less.
  • a lithium secondary battery with improved cycle characteristics as well as high-temperature storage characteristics can be implemented through the interaction of the main additive and the auxiliary additive.
  • the cyclic carbonate-based compound may include vinylene carbonate (VC), vinyl ethylene carbonate (VEC), etc.
  • the fluorine-substituted cyclic carbonate-based compound may include fluoroethylene carbonate (FEC).
  • FEC fluoroethylene carbonate
  • the sultone-based compounds include 1,3-propane sultone, 1,3-propene sultone, and 1,4-butane sultone. It may include etc.
  • the cyclic sulfate-based compound may include 1,2-ethylene sulfate, 1,2-propylene sulfate, etc.
  • the phosphate-based compound is an oxalatophosphate-based compound and may include lithium bis(oxalato)phosphate.
  • the auxiliary additive may be a fluorine-substituted cyclic carbonate-based compound, a sultone-based compound, a cyclic sulfate-based compound, and an oxalate-based compound.
  • the auxiliary additive By adding the auxiliary additive, the durability and stability of the electrode can be further improved.
  • the auxiliary additive may be included in an appropriate amount within a range that does not inhibit the movement of lithium ions in the electrolyte solution.
  • the organic solvent may include, for example, an organic compound that has sufficient solubility in the lithium salt, the additive, and the auxiliary additive and is not reactive in the battery.
  • the organic solvent may include at least one of a carbonate-based solvent, an ester-based solvent, an ether-based solvent, a ketone-based solvent, an alcohol-based solvent, and an aprotic solvent.
  • the organic solvent may include a carbonate-based solvent.
  • the carbonate-based solvent may include a linear carbonate-based solvent and a cyclic carbonate-based solvent.
  • the linear carbonate-based solvent includes dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), methyl propyl carbonate, and ethyl. It may include at least one of ethyl propyl carbonate and dipropyl carbonate.
  • the cyclic carbonate-based solvent may include at least one of ethylene carbonate (EC), propylene carbonate (PC), and butylene carbonate.
  • EC ethylene carbonate
  • PC propylene carbonate
  • butylene carbonate butylene carbonate
  • the organic solvent may include more of the linear carbonate-based solvent than the cyclic carbonate-based solvent, based on volume.
  • the mixing volume ratio of the linear carbonate-based solvent and the cyclic carbonate-based solvent may be 1:1 to 9:1, and preferably 1.5:1 to 4:1.
  • the ester-based solvent is methyl acetate (MA), ethyl acetate (EA), n-propyl acetate (n-PA), and 1,1-dimethylethyl acetate (DMEA). ; It may include at least one of 1,1-dimethylethyl acetate), methyl propionate (MP), and ethyl propionate (EP).
  • the ether-based solvent is dibutyl ether, tetraethylene glycol dimethyl ether (TEGDME), diethylene glycol dimethyl ether (DEGDME), and dimethoxyethane. ), tetrahydrofuran (THF), and 2-methyltetrahydrofuran (2-methyltetrahydrofuran).
  • the ketone-based solvent may include cyclohexanone.
  • the alcohol-based solvent may include at least one of ethyl alcohol and isopropyl alcohol.
  • the aprotic solvent includes a nitrile-based solvent, an amide-based solvent (e.g., dimethylformamide), a dioxolane-based solvent (e.g., 1,3-dioxolane), and a sulfolane-based solvent. It may contain at least one solvent.
  • the electrolyte contains a lithium salt, and the lithium salt can be expressed as Li +
  • the anion (X - ) of the lithium salt is F - , Cl - , Br - , I - , NO 3 - , N(CN) 2 - , BF 4 - , ClO 4 - , PF 6 - , (CF 3 ) 2 PF 4 - , (CF 3 ) 3 PF 3 - , (CF 3 ) 4 PF 2 - , (CF 3 ) 5 PF - , (CF 3 ) 6 P - , CF 3 SO 3 - , CF 3 CF 2 SO 3 - , (CF 3 SO 2 ) 2 N - , (FSO 2 ) 2 N - , CF 3 CF 2 (CF 3 ) 2 CO - , (CF 3 SO 2 ) 2 CH - , (SF 5 ) 3 C - , (CF 3 SO 2 ) 3 C - , CF 3 (CF 2 ) 7 SO 3 - , CF 3 CO 2
  • the lithium salt may include at least one of LiBF 4 and LiPF 6 .
  • the lithium salt may be included at a concentration of 0.01 to 5M, more preferably 0.01 to 2M, relative to the organic solvent. Within the above concentration range, lithium ions and/or electrons can be smoothly moved during charging and discharging of the battery.
  • a lithium secondary battery includes a positive electrode; cathode; a separator interposed between the anode and the cathode; and an electrolyte solution containing an organic solvent and a lithium salt.
  • FIG. 1 and 2 are schematic plan views and cross-sectional views, respectively, showing lithium secondary batteries according to example embodiments.
  • Figure 2 is a cross-sectional view taken along line II' of Figure 1.
  • a lithium secondary battery may include a positive electrode 100 and a negative electrode 130 opposing the positive electrode 100.
  • the positive electrode 100 may include a positive electrode current collector 105 and a positive electrode active material layer 110 on the positive electrode current collector 105.
  • the positive electrode active material layer 110 may include a positive electrode active material, a positive electrode binder, and a conductive material, if necessary.
  • the positive electrode 100 is prepared by mixing and stirring a positive electrode active material, a positive electrode binder, a conductive material, and a dispersion medium to prepare a positive electrode slurry, and then applying, drying, and rolling the positive electrode slurry on the positive electrode current collector 105. can be manufactured.
  • the positive electrode current collector 105 may include stainless steel, nickel, aluminum, titanium, copper, or alloys thereof.
  • the positive electrode active material may include lithium metal oxide particles capable of reversible insertion and desorption of lithium ions.
  • the positive electrode active material may include lithium metal oxide particles containing nickel.
  • the lithium metal oxide particles may contain 80 mol% or more of nickel based on the total number of moles of all elements excluding lithium and oxygen. In this case, a lithium secondary battery with high capacity can be implemented.
  • the lithium metal oxide particles may contain 83 mol% or more, 85 mol% or more, 90 mol% or more, or 95 mol% or more of nickel based on the total number of moles of all elements excluding lithium and oxygen.
  • the lithium metal oxide particles may further include at least one of cobalt and manganese.
  • the lithium metal oxide particles may further include cobalt and manganese.
  • a lithium secondary battery with excellent output characteristics and penetration stability can be implemented.
  • the lithium metal oxide particles may be represented by the following formula (2).
  • M is at least one of Al, Zr, Ti, Cr, B, Mg, Mn, Ba, Si, Y, W and Sr, 0.9 ⁇ x ⁇ 1.2, 1.9 ⁇ y ⁇ 2.1, It may be 0 ⁇ a+b ⁇ 0.5.
  • a+b is 0 ⁇ a+b ⁇ 0.4, 0 ⁇ a+b ⁇ 0.3, 0 ⁇ a+b ⁇ 0.2, 0 ⁇ a+b ⁇ 0.17, 0 ⁇ a+b ⁇ 0.15, It may be 0 ⁇ a+b ⁇ 0.12, 0 ⁇ a+b ⁇ 0.1.
  • the lithium metal oxide particles may further include a coating element or a doping element.
  • the coating element or doping element may include Al, Ti, Ba, Zr, Si, B, Mg, P, Sr, W, La, alloys thereof, or oxides thereof.
  • a lithium secondary battery with improved lifespan characteristics can be implemented.
  • the anode binder may be polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyacrylonitrile, or polymethyl methacrylate. It may include an organic binder such as polymethylmethacrylate; an aqueous binder such as styrene-butadiene rubber (SBR). Also, for example, the anode binder may be used with a thickener such as carboxymethyl cellulose (CMC).
  • PVDF polyvinylidene fluoride
  • PVDF-co-HFP vinylidene fluoride-hexafluoropropylene copolymer
  • SBR styrene-butadiene rubber
  • CMC carboxymethyl cellulose
  • the conductive material may include carbon-based conductive materials such as graphite, carbon black, graphene, and carbon nanotubes; Tin, tin oxide, titanium oxide; It may include metal-based conductive materials such as perovskite materials such as LaSrCoO 3 and LaSrMnO 3 .
  • the negative electrode 130 may include a negative electrode current collector 125 and a negative electrode active material layer 120 on the negative electrode current collector 125.
  • the negative electrode active material layer 120 may include a negative electrode active material, if necessary, a negative electrode binder, and a conductive material.
  • the negative electrode 130 is prepared by mixing and stirring a negative electrode active material, a negative electrode binder, a conductive material, a solvent, etc. to prepare a negative electrode slurry, and then applying, drying, and rolling the negative electrode slurry on the negative electrode current collector 125. can be manufactured.
  • the negative electrode current collector 125 may include gold, stainless steel, nickel, aluminum, titanium, copper, or an alloy thereof, or more preferably, copper or a copper alloy.
  • the negative electrode active material may be a material capable of inserting and desorbing lithium ions.
  • the negative electrode active material may include lithium alloy, carbon-based material, silicon-based material, etc.
  • the lithium alloy may include metal elements such as aluminum, zinc, bismuth, cadmium, antimony, silicon, lead, tin, gallium, and indium.
  • the carbon-based material may include crystalline carbon, amorphous carbon, carbon composite, carbon fiber, etc.
  • the amorphous carbon may be hard carbon, coke, mesocarbon microbeads (MCMB) fired at 1500°C or lower, mesophase pitch-based carbon fiber (MPCF), etc.
  • the crystalline carbon may be, for example, natural graphite, graphitized coke, graphitized MCMB, graphitized MPCF, etc.
  • the negative electrode active material may include a silicon-based material.
  • the silicon-based material may include Si, SiO x (0 ⁇ x ⁇ 2), Si/C, SiO/C, Si-Metal, etc. In this case, a lithium secondary battery with high capacity can be implemented.
  • Lithium secondary batteries can reduce the rate of increase in battery thickness by including the above-described electrolyte solution.
  • the content of the silicon active material in the negative electrode active material may include 1 to 20% by weight, 1 to 15% by weight, or 1 to 10% by weight.
  • the negative electrode binder and conductive material may be materials that are substantially the same as or similar to the positive electrode binder and conductive material described above.
  • the cathode binder may be an aqueous binder such as styrene-butadiene rubber (SBR).
  • SBR styrene-butadiene rubber
  • the anode binder may be used with a thickener such as carboxymethyl cellulose (CMC).
  • a separator 140 may be interposed between the anode 100 and the cathode 130.
  • the area of the cathode 130 may be larger than the area of the anode 100. In this case, lithium ions generated from the anode 100 can be smoothly moved to the cathode 130 without precipitating in the middle.
  • the separator 140 includes a porous polymer film made of polyolefin-based polymers, such as ethylene homopolymer, propylene homopolymer, ethylene/butene copolymer, ethylene/hexene copolymer, ethylene/methacrylate copolymer, etc. can do.
  • the separator 140 may include a non-woven fabric made of high melting point glass fiber, polyethylene terephthalate fiber, etc.
  • an electrode cell may be formed including an anode 100, a cathode 130, and a separator 140.
  • the electrode assembly 150 may be formed by stacking a plurality of electrode cells.
  • the electrode assembly 150 may be formed by winding, lamination, z-folding, etc. of the separator 140.
  • Lithium secondary batteries include a positive electrode lead 107 that is connected to the positive electrode 100 and protrudes to the outside of the case 160; and a negative electrode lead 127 that is connected to the negative electrode 130 and protrudes to the outside of the case 160.
  • the anode 100 and the anode lead 107 may be electrically connected.
  • the cathode 130 and the cathode lead 127 may be electrically connected.
  • the positive electrode lead 107 may be electrically connected to the positive electrode current collector 105.
  • the negative electrode lead 130 may be electrically connected to the negative electrode current collector 125.
  • the positive electrode current collector 105 may include a protrusion (positive electrode tab, not shown) on one side.
  • the positive electrode active material layer 110 may not be formed on the positive electrode tab.
  • the positive electrode tab may be integrated with the positive electrode current collector 105 or may be connected to the positive electrode current collector 105 by welding or the like.
  • the positive electrode current collector 105 and the positive electrode lead 107 may be electrically connected through the positive electrode tab.
  • the negative electrode current collector 125 may include a protrusion (negative electrode tab, not shown) on one side.
  • the negative electrode active material layer 120 may not be formed on the negative electrode tab.
  • the negative electrode tab may be integrated with the negative electrode current collector 125 or may be connected to the negative electrode current collector 125 by welding or the like.
  • the negative electrode current collector 125 and the negative electrode lead 127 may be electrically connected through the negative electrode tab.
  • the electrode assembly 150 may include a plurality of anodes and a plurality of cathodes.
  • a plurality of anodes and cathodes may be arranged alternately, and a separator may be interposed between the anode and the cathode.
  • a lithium secondary battery according to an embodiment of the present invention may include a plurality of positive electrode tabs and a plurality of negative electrode tabs protruding from each of the plurality of positive electrodes and the plurality of negative electrodes.
  • the positive electrode tabs may be laminated, pressed, and welded to form a positive electrode tab stack (or negative electrode tab stack).
  • the anode tab stack may be electrically connected to the anode lead 107.
  • the negative tab stack may be electrically connected to the negative electrode lead 127.
  • the electrode assembly 150 and the above-described electrolyte solution may be accommodated together in the case 160 to form a lithium secondary battery.
  • the lithium secondary battery may be manufactured in, for example, a cylindrical shape, a square shape, a pouch shape, or a coin shape.
  • a 1 M LiPF 6 solution (EC/EMC mixed solvent at a 25:75 volume ratio) was prepared.
  • Electrolytes of Examples and Comparative Examples were prepared by adding and mixing additives and auxiliary additives in the LiPF 6 solution in the amounts (% by weight) shown in Table 1 below, based on the total weight of the electrolyte.
  • a positive electrode slurry was prepared by dispersing Li[Ni 0.8 Co 0.1 Mn 0.1 ]O 2 , carbon black, and polyvinylidene fluoride (PVDF) in NMP at a weight ratio of 98:1:1.
  • the positive electrode slurry was uniformly applied to aluminum foil with a thickness of 12 ⁇ m, dried, and rolled to prepare a positive electrode.
  • the negative electrode active material is a mixture of artificial graphite and natural graphite at a weight ratio of 7:3, a conductive material, styrene-butadiene rubber (SBR), and carboxymethyl cellulose (CMC) dispersed in water at a weight ratio of 96:3:1:1 to form the negative electrode.
  • a slurry was prepared.
  • the negative electrode slurry was uniformly applied to copper foil with a thickness of 8 ⁇ m, dried, and rolled to prepare a negative electrode.
  • An electrode assembly was manufactured by repeatedly stacking the manufactured anodes and cathodes alternately, with a separator (13 ⁇ m thick, polyethylene film) interposed between the anode and cathode.
  • the electrode assembly was stored in a pouch, the electrolyte solution prepared in (2) above was injected, sealed, and impregnated for 12 hours to prepare a lithium secondary battery sample.
  • FEC Fluoroethylene carbonate
  • the lithium secondary batteries of Examples and Comparative Examples were repeatedly subjected to 0.5C CC/CV charging (4.2V, 0.05C CUT-OFF) and 0.5C CC discharging (2.7V CUT-OFF) three times at 25°C.
  • the second discharge capacity C1 was measured.
  • the charged lithium secondary battery was stored at 60°C for 12 weeks, then left at room temperature for an additional 30 minutes, and the discharge capacity C2 was measured by 0.5C CC discharge (2.75V CUT-OFF).
  • the capacity maintenance rate was calculated as follows and is listed in Table 2 below.
  • Capacity maintenance rate (%) C2/C1 ⁇ 100 (%)
  • the lithium secondary batteries of Examples and Comparative Examples were charged at room temperature at 0.5C CC/CV (4.2V 0.05C CUT-OFF) at 25°C and then discharged at 0.5C CC to SOC 60.
  • the C-rate was changed from 0.2C to 0.5C, 1C, 1.5C, 2C, and 2.5C, and DCIR R1 was measured by discharging and recharging for 10 seconds each.
  • the charged lithium secondary batteries of Examples and Comparative Examples were left in air exposure conditions at 60°C for 12 weeks, then left at room temperature for an additional 30 minutes, and DCIR R2 was measured in the same manner as described above.
  • the internal resistance increase rate was calculated as follows, and the results are listed in Table 2 below.
  • the lithium secondary batteries of Examples and Comparative Examples were charged at 0.5C CC/CV (4.2V 0.05C CUT-OFF) at 25°C, and then the battery thickness T1 was measured.
  • the charged lithium secondary batteries of Examples and Comparative Examples were left exposed to air at 60°C for 12 weeks (using a constant temperature device), and then the battery thickness T2 was measured. Battery thickness was measured using a flat plate thickness measuring device (Mitutoyo, 543-490B). The battery thickness increase rate was calculated as follows, and the results are listed in Table 2 below.
  • the lithium secondary batteries of Examples and Comparative Examples were charged at room temperature at 0.5C CC/CV (4.2V 0.05C CUT-OFF) at 25°C and then discharged at 0.5C CC to SOC 60.
  • the C-rate was changed to 0.2C, 0.5C, 1C, 1.5C, 2C, and 2.5C, and the initial DCIR was measured by discharging and supplementing for 10 seconds each, and the results are shown in Table 3 below.
  • the lithium secondary batteries of Examples and Comparative Examples were charged at 0.33C up to SOC (State of Charge) 8%, and 2.5C-2.25C-2C-1.75C-1.5C-1.0C step by step in the SOC 8 ⁇ 80% range. After charging to 0.33C (4.2V, 0.05C cut-off) in the SOC 80 ⁇ 100% range, CC discharged to 2.7V at 0.33C.
  • the discharge capacity A1 was measured at the first time, the charging and discharging were repeated 100 times, and the discharge capacity A2 was measured at the 100th time.
  • the fast charging capacity maintenance rate was calculated according to the formula below and is shown in Table 3 below.
  • the lithium secondary batteries of Examples and Comparative Examples were charged at 0.5C CC/CV (4.2V, 0.05C CUT-OFF) at 25°C, then left at -10°C for 4 hours and then discharged at 0.5C CC (2.7V CUT-OFF). ) and the discharge capacity (mAh) was measured and shown in Table 3 below.
  • 0.5C CC/CV charging (4.2V, 0.05C CUT-OFF) and 0.5C CC discharging (2.7V CUT-OFF) were repeated 500 times at 25°C.
  • the 1st discharge capacity was referred to as C
  • the 500th discharge capacity was divided by the 1st discharge capacity to measure the capacity maintenance rate during the lifespan and is shown in Table 3 below.
  • Example 1 88.0 105.4 83.6
  • Example 2 88.3 103.1 77.7
  • Example 3 89.2 107.8 60.2
  • Example 4 89.3 111.1 65.2 Comparative Example 1 88.2 108.6 96.2 Comparative example 2 86.1 115.5 116.4
  • the lithium secondary batteries of the examples showed excellent results in high temperature storage evaluation (capacity maintenance rate, resistance increase rate, and thickness increase rate).
  • the lithium secondary batteries of the examples showed good results in other performance (initial resistance, rapid charge life capacity maintenance rate, low temperature capacity, and room temperature life capacity maintenance rate).
  • Comparative Example 1 Comparative Example 2
  • Comparative Example 2 Comparative Example 2
  • the inclusion of PRS improves high temperature characteristics, but other performances are inferior.
  • the embodiments can improve other performances along with high-temperature storage performance.

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Abstract

La présente invention peut fournir un électrolyte pour une batterie au lithium rechargeable, comprenant : un additif comprenant un composé représenté par une formule chimique spécifique selon des modes de réalisation donnés à titre d'exemple ; un solvant organique et un sel de lithium. Par conséquent, une batterie au lithium rechargeable comprenant l'électrolyte pour une batterie au lithium rechargeable peut fournir d'excellentes caractéristiques à haute température et d'autres performances (par exemple, résistance initiale, performance de charge rapide, caractéristique de capacité à température ambiante, et analogue).
PCT/KR2023/006459 2022-05-19 2023-05-12 Électrolyte pour batterie au lithium rechargeable et batterie au lithium rechargeable le comprenant WO2023224322A1 (fr)

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Citations (4)

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US6350542B1 (en) * 1999-01-25 2002-02-26 Wilson Greatbatch Ltd. Sulfite additives for nonaqueous electrolyte rechargeable cells
EP1744394A1 (fr) * 2004-04-20 2007-01-17 Mitsubishi Chemical Corporation Solution electrolytique non aqueuse et accumulateur au lithium comprenant cette derniere
CN102185156A (zh) * 2011-04-13 2011-09-14 北京理工大学 一种电解液
KR102271011B1 (ko) * 2013-07-23 2021-06-29 고션 인코포레이티드 리튬 이온 배터리 중의 전해질에 대한 첨가제로서의 옥시란일 유도체

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KR102675258B1 (ko) 2018-01-30 2024-06-17 주식회사 엘지에너지솔루션 고온 저장 특성이 향상된 리튬 이차전지

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US6350542B1 (en) * 1999-01-25 2002-02-26 Wilson Greatbatch Ltd. Sulfite additives for nonaqueous electrolyte rechargeable cells
EP1744394A1 (fr) * 2004-04-20 2007-01-17 Mitsubishi Chemical Corporation Solution electrolytique non aqueuse et accumulateur au lithium comprenant cette derniere
CN102185156A (zh) * 2011-04-13 2011-09-14 北京理工大学 一种电解液
KR102271011B1 (ko) * 2013-07-23 2021-06-29 고션 인코포레이티드 리튬 이온 배터리 중의 전해질에 대한 첨가제로서의 옥시란일 유도체

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